[boost] MPL::void_t

From: Joel de Guzman (djowel_at_[hidden])
Date: 2003-01-24 00:21:05

Hi,

Question why is mpl::void_t an incomplete type? Sometimes I need
to instantiate it. For example to signal a zero arity functor call:

        typename actor_result<BaseT, tuple<> >::type
        operator()() const
        {
            return this->eval(void_t());
        }

        template <typename T0>
        typename actor_result<BaseT, tuple<T0> >::type
        operator()(T0& a0) const
        {
            return this->eval(a0);
        }

Of course I can do it differently, but it wouldn't be as clean and
generic as above. Thoughts?

Joel de Guzman
joel_at_[hidden]
http://www.boost-consulting.com